Waste disposal devices having odor-concealing systems are well known. Such waste disposal devices typically comprise a bag that is closed off by given mechanisms, to conceal the odors within the bag. U.S. Pat. No. 6,817,164 (Mauffette et al.) and U.S. Pat. No. 7,406,814 (Morand) propose such odor-concealing systems. However, it is desired to provide a waste disposal device that is simple in construction, and that may have the option of being opened by a pedal.